1. Field of the Invention
The present invention relates to a self locking adjustable screw, and in particular, to a screw which may be axially adjusted by screw action imposed through a wrench and which automatically unlocks with application of the wrench and locks on the removal of the wrench.
2. Description of Related Art
The subject invention relates to retaining screws and the like which may be tightened or loosened, and which require means for locking the screw in the desired position. Adjustable retaining screws or bolts are used in a variety of locations and the locking feature is necessary in environments where vibration may inadvertently loosen the screw or bolt. When such screws are used in an aircraft, they are frequently secured in the desired position by use of cotter keys or wires which pass through a bore in the bolt and are secured to a surrounding structure. The disadvantage of such securing mechanisms is the difficulty in adjusting or releasing the screw or bolt since the cotter key or wire must be removed prior to adjustment and replaced after the bolt is adjusted to the desired position.
The necessity for an automatically self-locking retaining screw or bolt is particular evident where the screw or bolt is used to hold heavy objects in position. For example, loading a weapon delivery system into the weapons bay of an aircraft requires placing the large, unweildy, heavy weapons delivery system in position while securing one or more downlock screws on the launcher end fittings to projections in the weapons bay. Securing the downlock screw in position after the weapon system is loaded in the bay is time consuming, could be dangerous, and is very difficult in view of the cramped space, particularly when a wire or other securing method is needed to lock the downlock screw in place.
Subject invention provides a self-locking adjustable screw which is easily adjusted to a desired position and automatically locks in that position after removal of the tool used to adjust the screw.